body {
    position: fixed;
    position: absolute;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
    background: url(../img/bj.png) no-repeat;
    background-size: cover;
}

.logon {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    width: 500px;
    height: 350px;
    border: 1px solid black;
    background-color: rgba(111, 148, 201, 0.3);
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    border-radius: 10px;
}

.logon strong {
    font-size: 30px;
}

.logon .input input {
    width: 400px;
    height: 30px;
    border-radius: 5px;
}

.logon .submit input {
    width: 400px;
    height: 40px;
    border-radius: 5px;
}

.input {
    margin: 50px 0;
}

.input p {
    position: relative;
    margin: 50px 0;
}

.input p .before {
    background: #000;
    color: #fff;
    position: absolute;
    top: -20px;
    left: 58px;
    padding: 2px 5px;
    font-size: x-small;
    display: none;
}

.input p .before:before {
    content: "";
    width: 0;
    height: 0;
    border: 5px solid transparent;
    border-top-color: black;
    position: absolute;
    top: 20px;
}

.after {
    color: #ff0000;
    font-size: x-small;
    display: none;
}